Abstract: Systems for maintain pointing of a phased array antenna in a direction maximizes to an extent possible the effective antenna gain is provided. The system includes a gyroscope and a Kalman Filter. The Kalman filter estimates an antenna pointing direction for each successive time step based on gyroscope readings and based on the results of a local search for maximum gain performed in the neighborhood of a previous antenna pointing direction.

Abstract: Multi-band quadrifilar antennas that are suitable for satellite communication include composite elements each of which include multiple conductors operating at different frequencies connected to a bus bar. Each composite element is coupled to a signal feed and to a ground structure.

Abstract: A system includes a phased array antenna that is used to emulate antennas that have larger solid angle coverage and lower gain compared to a single beam of the phased array antenna. This is achieved by switching between beams of the phased array antenna while receiving a wireless communication signal and summing representations of signal energy received using the different beams. The system can be used to narrow down the angular coordinates of a transmitting satellite by emulating antenna patterns that cover portions of a search space. The system can also be used to determine a channel discriminator (e.g., frequency, code, time slot) that defines a signal being transmitted.

Abstract: A tightly integrated combined transmit and receive dual quadrifilar antenna is provided. The antenna comprises four helical transmit elements and four helical receive elements disposed about a common axis. A receiver front end includes an arrangement of two 90 degree hybrids which serve to effectively reject signals cross coupled from the transmit elements back into the receive elements, while still allowing the receiver to receive signals.

Abstract: An antenna systems for a handheld wireless device comprises an antenna disposed proximate an oblong ground structure (e.g., oblong PCB). The antenna is suitably adapted to radiated circularly polarized waves by supporting quadrature phased first and second resonances which are associated with electrical fields oriented at right angles to each other and at an oblique angle relative to a longitudinal axis of the oblong ground structure.

Abstract: Antennas that include an inner set of four helical antenna elements and a co-axially arranged outer set of four helical antenna elements. The helical winding directions of the two sets of elements may have the same handedness or opposite handedness. Certain embodiments provide for switch handedness of circularly polarized radiation of the antennas and certain embodiments provide for shifting the directivity of the antenna pattern in polar angle. Systems in which the antennas are used and methods of use are also taught.

Abstract: An antenna systems for a handheld wireless device comprises an antenna disposed proximate an oblong ground structure (e.g., oblong PCB). The antenna is suitably adapted to radiated circularly polarized waves by supporting quadrature phased first and second resonances which are associated with electrical fields oriented at right angles to each other and at an oblique angle relative to a longitudinal axis of the oblong ground structure.

Abstract: Antennas that include an inner set of four helical antenna elements and a co-axially arranged outer set of four helical antenna elements. The helical winding directions of the two sets of elements may have the same handedness or opposite handedness. Certain embodiments provide for switch handedness of circularly polarized radiation of the antennas and certain embodiments provide for shifting the directivity of the antenna pattern in polar angle. Systems in which the antennas are used and methods of use are also taught.

Abstract: Multi-band quadrifilar antennas that are suitable for satellite communication include composite elements each of which include multiple conductors operating at different frequencies connected to a bus bar. Each composite element is coupled to a signal feed and to a ground structure.